Dolichos kongkandae sp. nov. and lectotypification of D. fragrans (Leguminosae, Papilionoideae) from Asia

Abstract Dolichos kongkandae is described as a new species from Asia and includes a line drawing, photographs and information on its distribution and ecology. The morphological differences between D. kongkandae and the morphologically similar D. tenuicaulis are highlighted and clarified. Additionally, a lectotype for D. fragrans is designated.


Introduction
Dolichos L. is a large genus in subtribe Phaseolinae, tribe Phaseoleae, subfamily Papilionoideae in Leguminosae (Lackey 1981;Schrire 2005). Its approximately 55 species mostly occur in Africa and only 5-6 species are found in Asia, including the Indian subcontinent, South China, Indo-China and Malesia (Schrire 2005).
There are several important diagnostic features of Dolichos. These include basifixed stipules, trifoliolate pinnately compound leaves, purple, purplish-pink or white flowers, a standard petal with short cone-shaped appendages and inflexed auricles, incurved, but not twisted keels, a terete and incurved upward-bending style with a short pubescent or bearded inner side of the apex, a terminal and capitate stigma, compressed fruits and reticulate pollen (Verdcourt 1970(Verdcourt , 1978(Verdcourt , 1979Lackey 1981; Moteetee and Van Wyk 2012).
During fieldwork at Doi Chiang Dao Wildlife Sanctuary in 2013 and 2017, a population of Dolichos that presented distinct dark purple flowers was discovered along the Khun Huai Mae Kok Ranger Station (Den Ya Khat) nature trail. We studied and compared this plant with available herbarium specimens of Dolichos and found that it was similar to specimens identified as D. tenuicaulis. After thorough examination of the type specimens and first publication of D. tenuicaulis, we found that our newly-collected plant and several of the herbarium specimens identified as D. tenuicaulis were not similar to the type specimens of D. tenuicaulis and that they differed from all the known species of Dolichos.
Here, we describe these collections as a new species, Dolichos kongkandae R. Meeboonya, Ngerns. & Balslev, with descriptions of its morphological features and we provide a line drawing and fields photographs. As part of our investigation, we found that D. fragrans Kerr, an endemic species from the Doi Chiang Dao Wildlife Sanctuary of Thailand, needed a lectotypification, which is consequently provided here.

Materials and methods
The morphological observations and description of this new species is based on field collections and herbarium specimens deposited at AAU, BK, BM, BKF, CMUB, E, K, L and P which were used to compare the new species to already-known species of Dolichos, especially the morphologically similar species and we provide the species' geographical information. Herbarium acronyms follow Index Herbariorum (Thiers 2019). Regarding the lectotypification of Dolichos fragrans, we designated a lectotype from five syntypes found at BM, E, K, L and P.
Conservation status. Dolichos kongkandae is widely distributed in its habitats. However, these areas are disturbed by the human activities. It is therefore considered as Near Threatened (NT), following the IUCN Red List Criteria and Categories version 14 (IUCN 2019). Notes. Dolichos kongkandae has been usually confused with D. tenuicaulis (Fig. 3) because of some morphological similarities. This is especially true of dried herbarium specimens.

Etymology. The specific epithet is named in honour of
The type specimens of Phaseolus tenuicaulis Baker (the basionym of D. tenuicaulis), Wallich Cat. no. 5598 D (holotype K001121419!), has a slightly pubescent stem, lanceolate, elliptic or subtriangular stipules, shorter axis of the inflorescence and the corolla turning pale yellow when dried. It also has a smaller standard, wing and keel petals and a slightly puberulous fruit stalk all of which distinguish it from D. kongkandae (Table 1). Craib (1912) published D. tenuicaulis, based on the specimens of Lace 4270 and Robertson 14. Moreover, he cited D. falcatus, based on the specimens of Housseus 45 and Kerr 834. We studied these specimens and found that Housseus 45, Kerr 834 and Robertson 14 are similar to D. tenuicaulis. However, the specimens of Lace 4270 have a densely-pubescent stem and leaves, ovate or broadly-elliptic stipules, longer axis of the inflorescence, densely-hirsute pedicel and the corolla turns to blackish-purple when dried; it has a larger standard, wing and keel petals and a hirsute fruit stalk which is not similar to D. tenuicaulis and these specimens are similar to D. kongkandae. Craib (1928) reported D. tenuicaulis as occurring in Thailand, based on the specimens Hosseus 45, Kerr 834,Kerr 4569,Kerr 6491,Kerr 6514,Put 322 and Winit 1542.  We studied these specimens and found they can be separated into two groups. We thoroughly examined the specimens of Dolichos from Thai and foreign herbaria. We consistently found that the herbarium specimens of D. kongkandae were  Notes. According to the protologue (Kerr 1941), the nomenclatural type of D. fragrans is H.B.G. Garrett 1167. Five syntypes of this gathering were deposited in BM, E, K, L and P and none of them has leaves (the leaves are often caducous when flowering). We designated the sheet K000900658 as the lectotype (Fig. 4), because it has many flowers and fruits, both of young and mature and also dissected flowers. The sheets, designated isolectotypes (BM000839653, E00275944, L1952810, P02775596), have fewer flowers and fruits than the sheet deposited at K and they have only flowers and young fruits, but no mature fruits.
The protologue also cites the specimens of Kerr 2854, Put 4480 and de Schauensee 719708. These specimens were also collected from the limestone mountain of Doi Chiang Dao Wildlife Sanctuary and they must be regarded as paratypes, according to Article 9.7 (Turland et al. 2018).